Preparation method of aquatic soft pellet feed

Abstract

The invention discloses a preparation method of an aquatic soft pellet feed, and the preparation method is as follows: rosemary extract, spina gleditsiae extract, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquin and bacillus subtilis are added into the soft pellet feed. The water in the soft pellet feed is converted from a free state to a combined state, so that the water in the soft pellet feed is not easy to lose even if the soft pellet feed is stored for a long time, and the soft pellet feed can play a bacteriostatic function, so that mould is not easy to proliferate under the condition that the water retention rate of the soft pellet feed is high. In addition, the preparation process of the soft pellet feed can also avoid loss of heat-sensitive components such as vitamins, the storage period is prolonged to 6 months or above, and the soft pellet feed has wide application prospects in the aspects of storage and breeding application of the soft pellet feed.

Description

Technical Field

[0001] This invention relates to the technical field of soft pellet feed, and more specifically, to a method for preparing aquatic soft pellet feed. Background Technology

[0002] With the large-scale and intensive development of aquaculture and livestock farming, feed, as a core material in the farming process, directly affects the growth performance, health status, and economic benefits of farmed animals. Soft pellet feed, due to its advantages such as good palatability, easy digestibility and absorption, minimal nutrient loss, and soft, elastic texture, better suits the natural feeding preferences of aquatic animals. Compared to hard pellet feed, soft pellet feed typically does not require high-temperature extrusion or secondary drying processes, and its moisture content is generally controlled between 20% and 30%. This moderate moisture content gives it its soft texture and excellent palatability.

[0003] However, soft pellet feed is highly susceptible to the technical challenge of rapid moisture evaporation during post-production storage and transportation, leading to feed hardening and severely impacting its quality and effectiveness. Specifically, a humidity difference exists between the internal moisture of soft pellet feed and the external environment. Under natural storage conditions, moisture diffuses and evaporates into the environment through the surface of the feed pellets. If the storage environment has a high temperature, rapid air circulation, or poor sealing of the storage container, the moisture evaporation process will be further accelerated. When the moisture content of soft pellet feed rapidly drops below 15%, the colloidal structure inside the pellets changes, altering the binding state of components such as proteins and starches. This causes the soft pellet feed to gradually harden and become brittle, even leading to clumping and powdering.

[0004] Hardening of feed has brought many adverse effects to aquaculture production: (1) The palatability of hardened soft pellet feed is significantly reduced, making it difficult for aquatic animals to eat and swallow, resulting in insufficient feed intake, slow growth, and even uneven growth; (2) The digestibility and absorption rate of hardened feed in the digestive tract of aquatic animals is reduced, which not only wastes feed resources and increases aquaculture costs, but also leaves undigested feed in the water or aquaculture environment, causing water quality deterioration or environmental pollution and increasing the risk of disease in aquatic animals. Studies have shown that long-term consumption of high-hardness feed is an important cause of enteritis in aquatic animals.

[0005] To address the storage issues of soft pellet feed, current technologies primarily employ conventional sealed bags, sealed drums, and other containers, or place humidifiers in the storage environment to increase humidity. However, conventional sealed containers cannot completely prevent the slow evaporation of moisture, and as storage time increases, uneven humidity environments can easily form inside the containers, failing to effectively prevent feed hardening. Furthermore, using environmental humidification, if humidity control is inadequate, can easily lead to the growth of mold and other microorganisms in the storage environment, causing feed spoilage and further damaging feed quality.

[0006] Therefore, developing a preparation method that can precisely control the rate of moisture evaporation during the storage of soft pellet feed, effectively prevent feed hardening, and ensure a safe storage environment that is not prone to microbial growth is of great significance for the storage and aquaculture application of soft pellet feed. Summary of the Invention

[0007] To overcome the aforementioned defects and shortcomings in the existing technology, the present invention provides a method for preparing aquatic soft pellet feed.

[0008] The first object of the present invention is to provide a composition for soft pellet feed.

[0009] A second object of the present invention is to provide the use of the above-described soft pellet feed composition as a water-retaining agent and / or mold inhibitor in the preparation of soft pellet feed.

[0010] A third objective of this invention is to provide a soft pellet feed.

[0011] The fourth objective of this invention is to provide a method for preparing soft pellet feed.

[0012] This invention claims protection for the following: A soft pellet feed composition comprising rosemary extract, soapberry thorn extract, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquinoline and Bacillus subtilis.

[0013] Preferably, the ratio of the amount of rosemary extract, soapberry thorn extract, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquinoline and Bacillus subtilis is (0.2-1):(0.8-1.2):(0.1-0.5):(0.2-0.5):(0.1-0.3):(1-3).

[0014] More preferably, the mass ratio of the rosemary extract, soapberry thorn extract, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquinoline and Bacillus subtilis is (0.2-1):1:(0.1-0.5):(0.2-0.5):0.2:2.

[0015] The above-mentioned soft pellet feed composition is used as a water-retaining agent and / or mold inhibitor in the preparation of soft pellet feed.

[0016] A soft pellet feed comprising the above-described soft pellet feed composition.

[0017] Preferably, the soft pellet feed further comprises main ingredients, algae powder, minerals, vitamins and feed additives; The main ingredients include three or four of the following: fish meal, chicken meal, wheat flour, and soybean meal. The algae powder includes spirulina powder; The feed additives include one or more of the following: tuna liver peptide, enzymatically hydrolyzed fish protein, propionic acid, tea polyphenols, resveratrol, vitamin E, vitamin C, glutathione, erythritol, phosphoric acid, salt, white sugar, glucose, molasses, cinnamaldehyde, andrographis paniculata extract and houttuynia cordata extract.

[0018] Preferably, the minerals include one or more of zinc, manganese, copper, iron, cobalt, iodine, and selenium; The vitamins mentioned include vitamin A, vitamin D3, vitamin E, vitamin K3, vitamin B1, vitamin B2, vitamin B6, and vitamin B1. 12 One or more of the following: vitamin C, D-calcium pantothenate, nicotinamide, folic acid, D-biotin, and inositol.

[0019] A method for preparing soft pellet feed, comprising adding the above-mentioned soft pellet feed composition to the soft pellet feed.

[0020] Preferably, the preparation method includes the following steps: S1. After mixing the main material and algae powder, adjust the moisture content of the mixture to a mass fraction of 15-18% to obtain the pretreated raw material; The main ingredients include three or four of the following: fish meal, chicken meal, flour, and soybean meal; the algae powder includes spirulina powder. S2. Add minerals to the pretreated raw materials and dry mix for 10-15 minutes to obtain a dry mixture; S3. Add the above-mentioned soft pellet feed composition and vitamins to the dry mixture, then control the temperature below 35°C and adjust the moisture content of the mixture to a mass fraction of 20-25%, mix for 5-8 minutes to obtain a wet mixture; S4. Feed the wet mixture into a conditioner and condition it at 85-90℃ for 30-60 seconds. After conditioning, pellet and cool it to obtain soft pellet feed.

[0021] In the production of soft pellet feed, moisture is not merely a simple humidity control measure, but a core process parameter for synergistic material mixing, activity protection, forming, and storage stability. In step S1, this invention precisely controls the moisture content to 15-18%, focusing on uniform mixing and pretreatment stability; in step S3, it precisely controls the moisture content to 20-25%, ensuring proper binding and activity protection during forming. This phased, precise control reflects the scientific nature and necessity of moisture management in feed processing, directly impacting the physical quality, nutrient retention rate, and breeding outcomes of the final product.

[0022] In addition to functioning as a water-retaining agent, the soft pellet feed composition also has an antibacterial effect. For example, Bacillus subtilis in the composition can inhibit the growth of mold, so that the total number of molds in the soft pellet feed is still below 10 cfu / g after 6 months of storage.

[0023] Preferably, in step S1, the amount of fish meal added is 50-60 parts by weight, the amount of chicken meal added is 5-10 parts, the amount of flour added is 5-10 parts, and the amount of soybean meal added is 5-20 parts.

[0024] Preferably, in step S1, the amount of spirulina powder added is 1 to 4 parts by weight.

[0025] Preferably, in step S2, the amount of minerals added is 0.5 to 1.5 parts by weight; and in step S3, the amount of vitamins added is 0.5 to 1.5 parts by weight.

[0026] Preferably, in step S2, the mineral includes one or more of zinc, manganese, copper, iron, cobalt, iodine, and selenium; In step S3, the vitamins include vitamin A, vitamin D3, vitamin E, vitamin K3, vitamin B1, vitamin B2, vitamin B6, and vitamin B6. 12 One or more of the following: vitamin C, D-calcium pantothenate, nicotinamide, folic acid, D-biotin, and inositol.

[0027] More preferably, each kilogram of feed contains: 3200-3700 mg of zinc, 2000-2400 mg of manganese, 800-840 mg of copper, 2400-2800 mg of iron, 100-140 mg of cobalt, 80-120 mg of iodine and 10-50 mg of selenium; The feed contains per kilogram: Vitamin A 740,000–760,000 IU, Vitamin D3 144,000–164,000 IU, Vitamin E 5,000–7,000 mg, Vitamin K3 1,660–2,060 mg, Vitamin B1 1,000–1,400 mg, Vitamin B2 1,000–1,400 mg, Vitamin B6 1,000–1,400 mg, Vitamin B2, and Vitamin B6. 12 6–10 mg, Vitamin C 20,000–22,000 mg, D-calcium pantothenate 4,600–5,000 mg, Nicotinamide 7,000–11,000 mg, Folic acid 350–390 mg, D-biotin 10–20 mg, and Inositol 7,000–9,000 mg.

[0028] More preferably, each kilogram of feed contains: 3500 mg of zinc, 2200 mg of manganese, 820 mg of copper, 2600 mg of iron, 120 mg of cobalt, 100 mg of iodine and 30 mg of selenium; The feed contains per kilogram: Vitamin A 750,000 IU, Vitamin D3 154,000 IU, Vitamin E 6,000 mg, Vitamin K3 1,860 mg, Vitamin B1 1,200 mg, Vitamin B2 1,200 mg, Vitamin B6 1,200 mg, Vitamin B... 12 8 mg, Vitamin C 21000 mg, D-calcium pantothenate 4800 mg, Nicotinamide 9000 mg, Folic acid 370 mg, D-Biotin 15 mg and Inositol 9000 mg.

[0029] Preferably, in step S3, feed additives are also added to the dry mixture, wherein the feed additives include one or more of the following: tuna liver peptide, enzymatically hydrolyzed fish protein, propionic acid, tea polyphenols, resveratrol, vitamin E, vitamin C, glutathione, erythritol, phosphoric acid, salt, white sugar, glucose, molasses, cinnamaldehyde, andrographis paniculata extract and houttuynia cordata extract.

[0030] As one feasible approach, the enzymatically hydrolyzed fish protein is the product of alkaline protease hydrolysis of fish surimi raw material; The rosemary extract was obtained by supercritical CO2 extraction. The Andrographis paniculata extract is an alcoholic extract of Andrographis paniculata; The soapberry thorn extract is an alcoholic extract of soapberry thorns; The houttuynia cordata extract is an aqueous extract of houttuynia cordata.

[0031] More preferably, the method for preparing the enzymatically hydrolyzed fish protein includes the following steps: S1. Mix the fish paste raw material with water at a mass ratio of 1:(3-5), adjust the pH to 7.0-8.5, add alkaline protease, the amount of alkaline protease added is 0.5%-1% of the dry basis mass of the fish paste raw material, and enzymatically hydrolyze at 40-55℃ for 10-14 h to obtain the enzymatic hydrolysate; S2. Heat the enzyme hydrolysate to 90-102℃ and maintain for 10-20 min to obtain the inactivated enzyme hydrolysate; remove the residue from the inactivated enzyme hydrolysate and collect the clear enzyme hydrolysate. S3. The clarified enzymatic hydrolysate is concentrated under vacuum at 50-60℃ and a vacuum degree of -0.08 to -0.095 MPa to obtain a concentrated solution; the concentrated solution is spray-dried under the following conditions: inlet air temperature 160-180℃ and outlet air temperature 75-85℃, thus obtaining enzymatically hydrolyzed fish protein.

[0032] More preferably, the method for preparing the enzymatically hydrolyzed fish protein includes the following steps: S1. Mix the fish paste raw material with water at a mass ratio of 1:4, adjust the pH to 8.0, add alkaline protease, the amount of alkaline protease added is 0.5% of the dry basis mass of the fish paste raw material, and enzymatically hydrolyze at 45℃ for 12 h to obtain the enzymatic hydrolysate; S2. Heat the enzyme hydrolysate to 100℃ and maintain for 10 min to obtain the inactivated enzyme hydrolysate; remove the residue from the inactivated enzyme hydrolysate and collect the clear enzyme hydrolysate. S3. The clarified enzymatic hydrolysate is concentrated under vacuum at 55℃ and -0.08 MPa to obtain a concentrated solution; the concentrated solution is spray-dried under the following conditions: inlet air temperature 160℃ and outlet air temperature 75℃, thus obtaining enzymatically hydrolyzed fish protein.

[0033] More preferably, the method for preparing the rosemary extract includes the following steps: S1. Rosemary was placed in a supercritical extraction vessel and extracted with carbon dioxide as the solvent. The extraction pressure was 25–35 MPa, the extraction temperature was 40–55 °C, the extraction time was 1.5–3 h, and the carbon dioxide flow rate was 20–30 L / h. After extraction, a CO2 fluid rich in extract was obtained. S2. Pass the CO2 fluid rich in extract into the separation vessel, adjust the pressure of the separation vessel to 5-8 MPa and the temperature to 30-40℃, so that the CO2 is vaporized and separated, and collect the crude extract; S3. Dissolve the crude extract in a 60-75% ethanol aqueous solution (v / v), stir at 45-55℃ for 20-40 min, then filter, concentrate the filtrate under reduced pressure at 50-60℃ and a vacuum of -0.08 to -0.10 MPa to obtain a concentrated extract; spray dry the concentrated extract at an inlet air temperature of 160-180℃ and an outlet air temperature of 70-90℃ to obtain rosemary extract.

[0034] More preferably, the method for preparing the rosemary extract includes the following steps: S1. Rosemary was placed in a supercritical extraction vessel and extracted with carbon dioxide as the solvent. The extraction pressure was 25 MPa, the extraction temperature was 45℃, the extraction time was 2 h, and the carbon dioxide flow rate was 25 L / h. After extraction, a CO2 fluid rich in extract was obtained. S2. Pass the CO2 fluid rich in extract into the separation vessel, adjust the pressure of the separation vessel to 6 MPa and the temperature to 30℃, so that the CO2 is vaporized and separated, and collect the crude extract; S3. Dissolve the crude extract in 75% ethanol aqueous solution (v / v), stir at 45℃ for 20 min, then filter, concentrate the filtrate under reduced pressure at 55℃ and vacuum degree -0.08 MPa to obtain concentrated extract; spray dry the concentrated extract at an inlet air temperature of 160℃ and an outlet air temperature of 70℃ to obtain rosemary extract.

[0035] More preferably, the preparation method of the Andrographis paniculata extract includes the following steps: S1. Mix Andrographis paniculata with 70-80% ethanol aqueous solution (v / v) at a material-to-liquid ratio of 1 g: (7-9) mL, and reflux extract at 75-85℃ 2-3 times, 1-2 h each time, and combine the extracts; S2. The combined extracts are concentrated under reduced pressure at 50-65℃ and a vacuum of -0.07 to -0.09 MPa to obtain concentrate A; activated carbon is added to concentrate A, the amount of activated carbon added is 1% to 3% of the mass of concentrate A, and the mixture is stirred and decolorized at 60-70℃ for 20-40 min, followed by filtration to obtain a clear filtrate. S3. Let the clarified filtrate stand at 4-10℃ for 12-24 h, then centrifuge to obtain the supernatant; spray dry the supernatant at an inlet air temperature of 150-170℃ and an outlet air temperature of 65-85℃ to obtain the Andrographis paniculata extract.

[0036] More preferably, the preparation method of the Andrographis paniculata extract includes the following steps: S1. Mix Andrographis paniculata with 75% ethanol aqueous solution (v / v) at a material-liquid ratio of 1 g: 8 mL, and reflux extract twice at 75℃ for 1 h each time, and combine the extracts; S2. The combined extracts were concentrated under reduced pressure at 55°C and -0.07 MPa to obtain concentrate A; activated carbon was added to concentrate A at 1% of the mass of concentrate A, and the mixture was stirred at 60°C for 30 min to decolorize, followed by filtration to obtain a clear filtrate. S3. The clarified filtrate was allowed to stand at 4°C for 24 h, and then centrifuged to obtain the supernatant. The supernatant was spray-dried at an inlet air temperature of 170°C and an outlet air temperature of 65°C to obtain the Andrographis paniculata extract.

[0037] More preferably, the preparation method of the soapberry thorn extract includes the following steps: S1. Mix the soapberry thorns with a 70-80% ethanol aqueous solution (v / v) at a material-to-liquid ratio of 1 g: (14-16) mL, and perform ultrasonic extraction at 45-55℃. The ultrasonic power is 300-500 W, the extraction time is 30-50 min, and the extraction is repeated 1-2 times. Combine the extracts. S2. The combined extracts are concentrated under reduced pressure at 55-65℃ and a vacuum of -0.08 to -0.095 MPa to obtain a concentrated extract; the concentrated extract is then vacuum dried or spray dried to obtain the soapberry thorn extract.

[0038] More preferably, the preparation method of the soapberry thorn extract includes the following steps: S1. Mix the soapberry thorns with 75% ethanol aqueous solution (v / v) at a material-liquid ratio of 1 g: 15 mL, and perform ultrasonic extraction at 55℃ with an ultrasonic power of 300 W and an extraction time of 30 min. Extract twice and combine the extracts. S2. The combined extracts were concentrated under reduced pressure at 55°C and -0.08 MPa to obtain a concentrated extract; the concentrated extract was then vacuum dried or spray dried to obtain the soapberry thorn extract.

[0039] More preferably, the preparation method of the houttuynia cordata extract includes the following steps: S1. Houttuynia cordata and water are mixed at a ratio of 1 g: (9-11) mL and placed in a sealed extraction tank. The mixture is extracted for 30-50 min at 120-140℃ and 0.2-0.4 MPa. Then, the mixture is rapidly cooled and depressurized, filtered, and separated to obtain extract A and filter residue. S2. Mix the filter residue with a 60-75% ethanol aqueous solution (v / v) at a material-to-liquid ratio of 1 g: (7-9) mL, reflux at 70-80℃ for 1-1.5 h, filter, and obtain extract B; S3. Combine extract A and extract B, and concentrate under reduced pressure at 55-65℃ and a vacuum of -0.08 to -0.095 MPa to obtain a concentrated solution; spray dry the concentrated solution at an inlet air temperature of 160-180℃ and an outlet air temperature of 75-85℃ to obtain houttuynia cordata extract.

[0040] More preferably, the preparation method of the houttuynia cordata extract includes the following steps: S1. Houttuynia cordata and water were mixed at a material-to-liquid ratio of 1 g: 10 mL and placed in a sealed extraction tank. The mixture was extracted for 30 min at 120℃ and 0.2 MPa. Then, the temperature and pressure were rapidly reduced, and the mixture was filtered to obtain extract A and filter residue. S2. Mix the filter residue with a 65% ethanol aqueous solution (v / v) at a material-to-liquid ratio of 1 g: 8 mL, reflux at 75°C for 1 h, filter, and obtain extract B; S3. Combine extract A and extract B, and concentrate under reduced pressure at 55℃ and -0.08 MPa to obtain a concentrated solution; spray dry the concentrated solution at an inlet air temperature of 160℃ and an outlet air temperature of 75℃ to obtain houttuynia cordata extract.

[0041] Preferably, in step S3, the total amount of the composition and feed additives added is 0.5 to 25% of the total weight of the main ingredients and auxiliary ingredients.

[0042] Preferably, in step S4, the granulation temperature is 60–70°C.

[0043] Preferably, in step S4, the cooling is performed in cold air at 15-20°C and cooled to 23-27°C within 10-15 minutes; after cooling, ultraviolet sterilization is also performed.

[0044] More preferably, after ultraviolet sterilization, the product is vacuum-packed or nitrogen-filled and then subjected to a sealing test.

[0045] The soft pellet feed prepared by the above method.

[0046] As one feasible approach, the soft pellet feed is an aquatic soft pellet feed.

[0047] Preferably, the aquatic soft pellet feed includes California bass soft pellet feed, mandarin fish soft pellet feed, and soft turtle soft pellet feed.

[0048] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for preparing aquatic soft pellet feed. The method involves adding rosemary extract, saponin thorn extract, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquin, and Bacillus subtilis to the soft pellet feed. This composition not only functions as a water-retaining agent, converting free water in the soft pellet feed into bound water, thus ensuring that the feed retains moisture even during extended storage, but also exerts antibacterial properties, preventing mold growth even with high moisture retention. Furthermore, the preparation process of this soft pellet feed avoids the loss of heat-sensitive components such as vitamins, extending the shelf life to over 6 months, demonstrating broad application prospects in the storage and aquaculture of soft pellet feed. Detailed Implementation

[0049] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0050] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0051] Tuna liver peptides: purchased from Guangzhou Lianmu Protein Biotechnology Co., Ltd. The method for preparing enzymatically hydrolyzed fish protein includes the following steps: (1) After cleaning and removing impurities from fresh low-value fish or fish processing by-products, mince them to a particle size ≤5 mm to obtain fish paste raw material. Mix the fish paste raw material with water at a mass ratio of 1:4, adjust the pH to 8.0, add alkaline protease (the amount of alkaline protease added is 0.5% of the dry basis mass of the fish paste raw material), and enzymatically hydrolyze at 45℃ for 12 h to obtain enzymatic hydrolysate; (2) Heat the enzyme hydrolysate to 100℃ and keep it for 10 min to terminate the enzyme hydrolysis reaction and obtain the inactivated enzyme hydrolysate; remove the residue by centrifugation or pressure filtration and collect the clear enzyme hydrolysate. (3) The clarified enzymatic hydrolysate was concentrated under vacuum at 55°C and -0.08 MPa to obtain a concentrated solution; the concentrated solution was spray-dried; the spray-drying conditions were: inlet air temperature 160°C and outlet air temperature 75°C, thus obtaining enzymatically hydrolyzed fish protein.

[0052] The preparation method of rosemary extract includes the following steps: (1) After washing and drying the rosemary branches and leaves, they were pulverized to 40 mesh to obtain rosemary raw material powder. The rosemary raw material powder was placed in a supercritical extraction vessel and extracted with carbon dioxide as solvent. The extraction pressure was 25 MPa, the extraction temperature was 45℃, the extraction time was 2 h, and the carbon dioxide flow rate was 25 L / h. After the extraction was completed, a CO2 fluid rich in extract was obtained. (2) Pass CO2 fluid rich in extract into the separation vessel, adjust the pressure of the separation vessel to 6 MPa and the temperature to 30℃, so that CO2 is vaporized and separated, and collect the dark green paste-like crude extract at the bottom of the vessel; (3) Dissolve the crude extract in a 75% ethanol aqueous solution (v / v), stir at 45°C for 20 min, then filter, concentrate the filtrate under reduced pressure at 55°C and a vacuum of -0.08 MPa, recover the ethanol, and obtain a concentrated extract. Spray dry the concentrated extract at an inlet air temperature of 160°C and an outlet air temperature of 70°C to obtain rosemary extract.

[0053] The preparation method of Andrographis paniculata extract includes the following steps: (1) The dried whole herb of Andrographis paniculata was pulverized and passed through a 40-mesh sieve to obtain Andrographis paniculata raw material powder. The Andrographis paniculata raw material powder was mixed with 75% ethanol aqueous solution (v / v) at a material-liquid ratio of 1 g: 8 mL, and refluxed twice at 75℃ for 1 h each time. The extracts were combined. (2) The combined extracts were concentrated under reduced pressure at 55℃ and a vacuum of -0.07 MPa to recover ethanol and obtain concentrate A. Activated carbon (1% of the mass of concentrate A) was added to concentrate A and stirred at 60℃ for 30 min to decolorize. Then the solution was filtered to obtain a clear filtrate. (3) The clarified filtrate was allowed to stand at 4°C for 24 h to allow the colloids and some impurities to precipitate. After centrifugation, the supernatant was obtained. The supernatant was spray-dried at an inlet air temperature of 170°C and an outlet air temperature of 65°C to obtain Andrographis paniculata extract.

[0054] The preparation method of soapberry thorn extract includes the following steps: (1) After slicing the dried soapberry thorns, crush them and pass them through a 40-mesh sieve to obtain soapberry thorn raw material powder. Mix the soapberry thorn raw material powder with 75% ethanol aqueous solution (v / v) at a material-liquid ratio of 1 g: 15 mL, and perform ultrasonic extraction at 50℃ with an ultrasonic power of 300 W and an extraction time of 30 min. Extract twice and combine the extracts. (2) The combined extracts were concentrated under reduced pressure at 55°C and -0.08 MPa to recover ethanol and obtain concentrated extract. The concentrated extract was then vacuum dried or spray dried to obtain soapberry thorn extract.

[0055] The preparation method of Houttuynia cordata extract includes the following steps: (1) Wash the whole fresh Houttuynia cordata plant, drain the water and cut it into sections. Dry it in a forced-air drying at 55℃ until the moisture content is ≤10%. Grind it through a 40-mesh sieve to obtain Houttuynia cordata raw powder. Mix the Houttuynia cordata raw powder with deionized water at a material-to-liquid ratio of 1 g:10 mL, place it in a sealed extraction tank, and extract it at 120℃ and 0.2 MPa for 30 min. Then, rapidly cool and depressurize it, filter and separate it to obtain extract A and filter residue. (2) Mix the filter residue with 65% ethanol aqueous solution (v / v) at a material-liquid ratio of 1 g: 8 mL, reflux at 75℃ for 1 h, filter, and obtain extract B; (3) Combine extract A and extract B, and concentrate under reduced pressure at 55℃ and -0.08 MPa to obtain a concentrated solution. Spray dry the concentrated solution at an inlet air temperature of 160℃ and an outlet air temperature of 75℃ to obtain the houttuynia cordata extract.

[0056] The Bacillus subtilis used in the examples and comparative examples was Bacillus subtilis YXSY-01, with strain preservation number GDMCC No: 64078 and Chinese invention patent CN117568235A. The viable count of this inoculum was 0.5 × 10⁻⁶. 7 CFU / g ~ 2×10 7 CFU / g.

[0057] Vitamin premix (mg or IU / kg feed): Vitamin A: 750,000 IU, Vitamin D3: 154,000 IU, Vitamin E: 6,000 mg, Vitamin K3: 1,860 mg, Vitamin B1: 1,200 mg, Vitamin B2: 1,200 mg, Vitamin B6: 1,200 mg, Vitamin B... 12 8 mg, Vitamin C: 21000 mg, D-calcium pantothenate: 4800 mg, Nicotinamide: 9000 mg, Folic acid: 370 mg, D-biotin: 15 mg, Inositol: 9000 mg; Mineral premix (mg / kg feed): Zinc: 3500 mg, Manganese: 2200 mg, Copper: 820 mg, Iron: 2600 mg, Cobalt: 120 mg, Iodine: 100 mg, Selenium: 30 mg.

[0058] Example 1: A method for preparing soft pellet feed for California bass This embodiment provides a soft pellet feed for California bass, comprising the following components in parts by weight: 50 parts fish meal, 16 parts chicken meal, 10 parts wheat flour, 10 parts soybean meal, 4 parts spirulina powder, 1 part vitamin premix, 1 part mineral premix, 0.1 part butylated hydroxyanisole (BHA), 0.2 part butylated hydroxytoluene (BHT), 3 parts tuna liver peptide, 0.1 part phosphoric acid, 1.4 parts salt, 1 part white sugar, 1 part glucose, 0.2 parts rosemary extract, 0.1 part andrographis paniculata extract, 1 part soapberry thorn extract, 0.2 parts ethoxyquin, and 2 parts Bacillus subtilis.

[0059] The California bass soft pellet feed was prepared using the following method: S1. Preparation and Grinding of Main Ingredients: Take 50 parts fish meal, 16 parts chicken meal, 10 parts wheat flour and 10 parts soybean meal as main ingredients; take 4 parts spirulina powder as auxiliary ingredients; grind the main ingredients and auxiliary ingredients separately, pass them through a 0.2 mm sieve to remove impurities, and then mix them evenly. S2. Pretreatment of raw materials for moisture control: After mixing, spray water to replenish the moisture content to 16% (w / w), filter through a 1.2 mm sieve to obtain the pretreated raw materials; S3. Dry mixing of small ingredients: Add 1 part of mineral premix to the pretreated raw materials and dry mix in a twin-shaft mixer for 13 minutes until the homogeneity reaches 96%; S4. Temperature-controlled wet mixing: Add 1 part of vitamin premix, and slowly add 0.1 part of butylated hydroxyanisole (BHA), 0.2 part of butylated hydroxytoluene (BHT), 3 parts of tuna liver peptide, 0.1 part of phosphoric acid, 1.4 parts of salt, 1 part of white sugar, 1 part of glucose, 0.2 parts of rosemary extract, 0.1 part of andrographis paniculata extract, 1 part of soapberry thorn extract, 0.2 parts of ethoxyquinoline, and 2 parts of Bacillus subtilis. While cooling to 30°C using a spray gun, add water to bring the total moisture content to 22%. Stir for 6 minutes until there are no local lumps. S5. High-temperature short-time conditioning: The mixture is fed into a conditioner, saturated steam at 0.3 MPa is introduced, and the temperature is controlled at 87℃ for 45 seconds, achieving a 95% sterilization rate of mold spores; S6. Granulation: Ring die granulator, 3 mm aperture, granulation temperature controlled at 65℃, cut into 3 mm long particles, no cracks; S7. Cooling: Cool under 18℃ cold air for 12 min, cool to 25℃, moisture retention rate 98.7% (w / w); S8. After UV sterilization, packaging, and testing for airtightness, the California bass soft pellet feed is obtained.

[0060] Example 2: A method for preparing soft pellet feed for mandarin fish This embodiment provides a soft pellet feed for mandarin fish, comprising the following components in parts by weight: The ingredients are: 60 parts fish meal, 5 parts chicken meal, 5 parts wheat flour, 17 parts soybean meal, 2 parts spirulina powder, 1 part vitamin premix, 1 part mineral premix, 0.1 part butylated hydroxyanisole (BHA), 0.2 parts butylated hydroxytoluene (BHT), 5 parts enzymatically hydrolyzed fish protein, 1 part propionic acid, 0.5 parts tea polyphenols, 0.5 parts resveratrol, 0.1 parts vitamin E, 0.1 parts vitamin C, 0.3 parts glutathione, 0.5 parts erythritol, 0.2 parts phosphoric acid, 1 part molasses, 0.5 parts cinnamaldehyde, 1 part soapberry thorn extract, 1 part rosemary extract, 0.2 parts ethoxyquin, and 2 parts Bacillus subtilis. The soft pellet feed for mandarin fish is prepared using the following method: S1. Preparation and Grinding of Ingredients: Take 60 parts fish meal, 5 parts chicken meal, 5 parts wheat flour and 17 parts soybean meal as the main ingredients; 2 parts spirulina powder as the auxiliary ingredients; grind the main ingredients and auxiliary ingredients separately, pass them through a 0.4 mm sieve to remove impurities, and then mix them evenly. S2. Pre-treatment of raw materials for moisture control: After mixing, spray water to replenish the moisture content to 15% (w / w), filter through a 1.2 mm sieve to obtain the pre-treated raw materials; S3. Dry mixing of small ingredients: Add 1 part of mineral premix to the pretreated raw materials and dry mix in a twin-shaft mixer for 15 minutes until the homogeneity reaches 98%; S4. Temperature-controlled wet mixing: Add 1 part of vitamin premix, and slowly add 0.1 part of butylated hydroxyanisole (BHA), 0.2 part of butylated hydroxytoluene (BHT), 5 parts of enzymatically hydrolyzed fish protein, 1 part of propionic acid, 0.5 part of tea polyphenols, 0.5 part of resveratrol, 0.1 part of vitamin E, 0.1 part of vitamin C, 0.3 part of glutathione, 0.5 part of erythritol, 0.2 part of phosphoric acid, 1 part of molasses, 0.5 part of cinnamaldehyde, 1 part of soapberry thorn extract, 1 part of rosemary extract, 0.2 part of ethoxyquinoline, and 2 parts of Bacillus subtilis. While cooling to 30°C using a spray gun, add water until the total moisture content reaches 23% (w / w), and stir for 5 minutes until there are no local lumps. S5. High-temperature short-time conditioning: The mixture is fed into a conditioner, saturated steam at 0.35 MPa is introduced, and the temperature is controlled at 88℃ for 50 seconds, achieving a mold spore sterilization rate of 96%. S6. Granulation: Ring die granulator, 2 mm aperture, granulation temperature controlled at 62℃, cut into 2 mm long strips, no cracks; S7. Cooling: Cool under 16℃ cold air for 11 min, cool to 24℃, moisture retention rate 98.9% (w / w). S8. UV sterilization, vacuum packaging (-0.098 MPa), and pass the sealing test to obtain mandarin fish soft pellet feed.

[0061] Example 3: A method for preparing soft pellet feed for soft-shelled turtles This embodiment provides a soft pellet feed for turtles, comprising the following components in parts by weight: 55 parts white fish meal, 10 parts chicken meal, 10 parts wheat flour, 6 parts soybean meal, 1 part spirulina powder, 1 part vitamin premix, 1 part mineral premix, 0.5 parts butylated hydroxyanisole (BHA), 0.5 parts butylated hydroxytoluene (BHT), 3 parts tuna liver peptide, 2 parts enzymatically hydrolyzed fish protein, 1 part propionic acid, 1 part erythritol, 1 part phosphoric acid, 1 part salt, 1 part glucose, 2 parts molasses, 2 parts houttuynia cordata extract, 0.2 parts rosemary extract, 1 part soapberry thorn extract, 0.2 parts ethoxyquin, and 2 parts Bacillus subtilis.

[0062] The soft pellet feed for turtles is prepared using the following method: S1. Preparation and Grinding of Main Ingredients: Take 55 parts of white fish meal, 10 parts of chicken meal, 10 parts of flour and 6 parts of soybean meal as the main ingredients; take 1 part of spirulina powder as the auxiliary ingredient; grind the main ingredients and auxiliary ingredients separately, pass them through a 0.4 mm sieve to remove impurities, and then mix them evenly. S2. Pretreatment of raw materials for moisture control: After mixing, spray water to replenish the moisture content to 17% (w / w), filter through a 1.2 mm sieve to obtain the pretreated raw materials; S3. Dry mixing of small ingredients: Add 1 part of mineral premix to the pretreated raw materials and dry mix in a twin-shaft mixer for 14 minutes until the homogeneity reaches 97%; S4. Temperature-controlled wet mixing: Add 1 part of vitamin premix, and slowly add 0.5 parts of butylated hydroxyanisole (BHA), 0.5 parts of butylated hydroxytoluene (BHT), 3 parts of tuna liver peptide, 2 parts of enzymatically hydrolyzed fish protein, 1 part of propionic acid, 1 part of erythritol, 1 part of phosphoric acid, 1 part of salt, 1 part of glucose, 2 parts of molasses, 2 parts of houttuynia cordata extract, 0.2 parts of rosemary extract, 1 part of soapberry thorn extract, 0.2 parts of ethoxyquinoline, and 2 parts of Bacillus subtilis. While cooling to 28°C using a spray gun, add water until the total moisture content reaches 23% (w / w), and stir for 7 minutes until there are no local lumps. S5. High-temperature short-time conditioning: The mixture is fed into a conditioner, saturated steam at 0.38 MPa is introduced, and the temperature is controlled at 89℃ for 50 seconds, achieving a mold spore sterilization rate of 93%. S6. Granulation: Ring die granulator, 4 mm aperture, granulation temperature controlled at 62℃, cut into 4 mm long granules, without cracks; S7. Cooling: Cooled for 11 minutes under 16℃ cold air to a temperature of 23℃, with a moisture retention rate of 98.8%; S8. UV sterilization, nitrogen-filled packaging (38% air volume, -0.098 MPa), and sealing test results in soft pellet feed for turtles.

[0063] Comparative Example 1 This comparative example was prepared according to Example 1, with the difference that in step S4, rosemary extract, soapberry thorn extract, butylated hydroxyanisole, dibutylated hydroxytoluene, ethoxyquinoline and Bacillus subtilis were not added.

[0064] Comparative Example 2 This comparative example was prepared according to Example 1 to produce soft pellet feed for California bass. The difference was that in step S4, rosemary extract was replaced with Eucommia ulmoides leaf extract, wherein the Eucommia ulmoides leaf extract was prepared according to the optimal extraction conditions in "Optimization of Supercritical Fluid Extraction Process of Total Flavonoids from Eucommia ulmoides Leaf and Liquid Chromatography-Mass Analytical Analysis of its Components".

[0065] Comparative Example 3 This comparative example prepared soft pellet feed for mandarin fish according to Example 2, except that in step S4, rosemary extract, soapberry thorn extract, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquinoline and Bacillus subtilis were not added.

[0066] Comparative Example 4 This comparative example prepared soft pellet feed for mandarin fish according to Example 2, except that in step S4, the extract of soapberry thorn was replaced with mulberry leaf extract, wherein the mulberry leaf extract was prepared according to the optimal extraction conditions in "Optimization of Extraction Process of Mulberry Leaf Alcohol Extract and its Application in Meat Preservation".

[0067] Comparative Example 5 This comparative example prepared soft pellet feed for turtles according to Example 3, except that in step S4, rosemary extract, soapberry thorn extract, butylated hydroxyanisole, dibutylated hydroxytoluene, ethoxyquinoline and Bacillus subtilis were not added.

[0068] Comparative Example 6 This comparative example prepared soft pellet feed for turtles according to Example 3, except that in step S4, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were replaced with tert-butylhydroquinone (TBHQ) and propyl gallate (PG), respectively.

[0069] Example 4: Moisture retention rate of soft pellet feed after 6 months of storage I. Experimental Methods The soft pellet feeds prepared in Examples 1-3 and Comparative Examples 1-6 were stored under the same conditions for 6 months, and their moisture retention rate and bound water content were tested.

[0070] Method for determining moisture retention: Accurately determine the moisture content of the sample using the direct drying method as described in GB / T 6435-2014, and compare the moisture data at two time points: freshly made soft pellet feed (point A) and soft pellet feed sample stored for 6 months (point B). Soft pellet feed samples must be sealed immediately after sampling and tested rapidly to prevent water loss from affecting the results. After determining the moisture content, calculate it using the following formula: Moisture content (W, %) = (M1 - M2) / M1 × 100%; Moisture retention rate (%) = (W B / W A ) × 100%.

[0071] Where: M1 is the sample size of the soft pellet feed; M2 is the weight of the cooled soft pellet feed; W A Moisture content at time point A; W B Moisture content at time point B.

[0072] Referring to the prior art (10.1016 / 0040-6031(88)80018-2) and the prior art (10.1016 / j.enconman.2008.06.002), the weight loss data of soft pellet feed was determined by thermogravimetric analysis (TG), the drying rate curve was plotted, the critical temperature at which the evaporation of free water ends and the evaporation of bound water begins was determined, and the bound water content of the soft pellet feed prepared in Examples 1-3 and Comparative Examples 1-6 after being stored under the same conditions for 6 months was calculated accordingly.

[0073] II. Experimental Results Table 1 shows that after 6 months of storage, the moisture content of the soft pellet feeds in Examples 1-3 was significantly higher than that in Comparative Examples 1-6, indicating that rosemary extract, soapberry thorn extract, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquin, and Bacillus subtilis acted as water-retaining agents in the soft pellet feeds of Examples 1-3. It is precisely the addition of these compositions that enabled the prepared soft pellet feed to retain moisture for a longer storage period and also increased the bound water content of the soft pellet feed, causing the moisture in the soft pellet feed to change from a free state to a bound state.

[0074] Table 1. Moisture retention rate and bound water content of soft pellet feed after 6 months of storage

[0075] Example 5: Total mold count, B vitamin retention rate, and Bacillus subtilis survival rate of soft pellet feed after 6 months of storage. I. Experimental Methods After storing the soft pellet feeds prepared in Examples 1-3 and Comparative Examples 1-6 under the same conditions for 6 months, the total number of molds, the retention rate of B vitamins, and the survival rate of Bacillus subtilis were tested.

[0076] Method for detecting total mold count: Determine the total mold count in soft pellet feed according to GB / T 13092-2006.

[0077] The method for detecting the retention rate of B vitamins is as follows: High performance liquid chromatography (HPLC) is used. The specific detection method is as follows: (1) Sample pretreatment: Accurately weigh the soft pellet feed sample, and after enzymatic hydrolysis with amylase (10 mg of amylase per gram of soft pellet feed sample) and protease (20 mg of protease per gram of soft pellet feed sample), extract vitamins with 0.1 mol / L hydrochloric acid buffer to obtain the pretreatment solution; (2) Instrumental analysis: The pretreatment solution was injected into the HPLC system. Each vitamin was separated in the chromatographic column (C18 column) by the mobile phase (phase A: phosphate buffer, phase B: methanol). They were eluted sequentially according to different retention times and then detected by ultraviolet or fluorescence detectors. (3) Qualitative and quantitative analysis: Qualitative analysis is performed by comparing the retention times of the peaks of each vitamin standard and the sample, and the content is calculated by using the peak area through the standard curve method or the external standard method. (4) Calculation of results: Based on the weight of the soft pellet feed sample, the dilution ratio and the measured value of vitamins, the actual content of B vitamins in the soft pellet feed (mg / kg) was calculated.

[0078] Method for detecting the survival rate of Bacillus subtilis: The detection method shall be performed in accordance with the method specified in GB / T 26428-2010 "Detection of Bacillus subtilis in feed microbial preparations".

[0079] II. Experimental Results The results in Table 2 show that after 6 months of storage, the soft pellet feed prepared in Examples 1-3 had a total mold count ≤10 cfu / g, a B vitamin retention rate ≥85%, and a Bacillus subtilis survival rate ≥90%, which is far superior to the soft pellet feed prepared in Comparative Examples 1-6.

[0080] In the soft pellet feeds prepared in Examples 1-3, rosemary extract, soapberry thorn extract, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquinoline, and Bacillus subtilis not only function as water-retaining agents but also as antibacterial agents. For example, Bacillus subtilis can inhibit mold, so that the soft pellet feeds prepared in Examples 1-3 can reduce mold growth while maintaining a high moisture retention rate.

[0081] Table 2. Total mold count, B vitamin retention rate, and Bacillus subtilis survival rate of soft pellet feed after 6 months of storage.

[0082] Note: Comparative Examples 1, 3, and 5 did not contain Bacillus subtilis, so there was no need to test the survival rate of Bacillus subtilis.

[0083] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A composition for soft pelleted feed, characterized by, The composition comprises rosemary extract, horntree spine extract, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquin and bacillus subtilis.

2. The soft pelleted feed composition according to claim 1, characterized in that, The mass ratio of the rosemary extract, horntree spine extract, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquin and bacillus subtilis is (0.2-1):(0.8-1.2):(0.1-0.5):(0.2-0.5):(0.1-0.3):(1-3).

3. Use of the soft pellet feed composition of claim 1 or 2 as or in the preparation of a water retaining agent and / or a mold inhibitor for soft pellet feed.

4. A soft pellet feed, characterized by The soft pellet feed comprises the soft pellet feed composition of claim 1 or 2.

5. Soft pellet feed according to claim 4, characterized in that The soft pellet feed further comprises a main material, algal powder, mineral, vitamin and feed additive; The main material comprises three or four of fish meal, chicken meal, wheat flour and soybean meal; The algal powder comprises spirulina powder; The feed additive comprises one or more of tuna liver peptide, enzymatic fish protein, propionic acid, tea polyphenol, resveratrol, vitamin E, vitamin C, glutathione, erythritol, phosphoric acid, table salt, white granulated sugar, glucose, molasses, cinnamaldehyde, andrographis extract and houttuynia cordata extract.

6. The soft pelleted feed according to claim 5, characterized in that, The mineral comprises one or more of zinc, manganese, copper, iron, cobalt, iodine and selenium; The vitamins include one or several of vitamin A, vitamin D3, vitamin E, vitamin K3, vitamin B1, vitamin B2, vitamin B6, vitamin B 12 12, vitamin C, calcium D-pantothenate, nicotinamide, folic acid, D-biotin and inositol.

7. A method of preparing soft pellet feed, characterized by, The soft pellet feed composition of claim 1 or 2 is added to the soft pellet feed.

8. The preparation method according to claim 7, characterized in that, The preparation method comprises the following steps: S1. The main material and the algal powder are mixed, and the moisture content of the mixture is adjusted to 15-18% by mass fraction to obtain pretreated raw material; The main material comprises three or four of fish meal, chicken meal, wheat flour and soybean meal, and the algal powder comprises spirulina powder; S2. The mineral is added to the pretreated raw material, and the dry mixture is obtained after dry mixing for 10-15 min; S3. The soft pellet feed composition of claim 1 or 2 and the vitamin are added to the dry mixture, and then the temperature is controlled below 35℃ and the moisture content of the mixture is adjusted to 20-25% by mass fraction, and the mixture is mixed for 5-8 min to obtain wet mixture; S4. The wet mixture is sent to a conditioner, and conditioned at 85-90℃ for 30-60 s, and then granulated and cooled to obtain the soft pellet feed.

9. The production method according to claim 8, characterized by, In step S3, the feed additive is also added to the dry mixture, and the feed additive comprises one or more of tuna liver peptide, enzymatic fish protein, propionic acid, tea polyphenol, resveratrol, vitamin E, vitamin C, glutathione, erythritol, phosphoric acid, table salt, white granulated sugar, glucose, molasses, cinnamaldehyde, andrographis extract and houttuynia cordata extract.

10. The soft pellet feed prepared by the preparation method of any one of claims 7-9.

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